Improvement in chucks for rock-drills



l H. THOMAS. Chucks for Ruck-Drills.

Patented Oct. 19, 1875.

4UNITEE STATES PATENT OEEICE.

,HUGH THoMAs, 0E NEW YORK, N. Y. i

IMPROVEMENT IN CHUCKS FOR ROCK-DRILLS.

Specication forming partvof Letters Patent No. 168,938, dated October 19, 1875; application filed October 7, 1875.

To all whom it may concern.-

.Be it known that I, HUGH THOMAS, of the city of New York, State'of New York, have invented a new and useful Improvement in Rock-Drills, which improvement is fully set forth in the following specification, reference being had to the accompanying drawings.

This improvement relates to improvements in vapparatus for drilling holes in rock or other hard substances, in which apparatus pistons carrying a drill are made to reciprocate or revolve by the force of steam, air, or otherv power.

. line B D, Fig'. 3 5 and Fig. 3 is a transverse -sec-A tion through the line B D, Fig. 2.l

Similar letters of reference indicate corre sponding parts in the several figures.

In the annexed drawings, the chuck A has a split cut on each side, as shown at E, the full depth of the holevO, so that the sides of the chuck can be sprung closer together. The

purpose described.

chuck also has av chuck-bolt, B D, tted to it, with a shoulder or projection at d, Figs. 2 and 3, bearing against one side of thechuck. The hole in the bolt at G is made an oval shape, to allow the bolt a movement edgewise without touching the drill, which is inserted in the hole C. The bolt is made. somewhat -shorter than the hole in the chuck, also to allow an end motion of the bolt, as shown at a, so that when the two sides ofthe chuck are forced together about the drill in the hole there will still be a clearance for the bolt, and the sides will not jam on it. Now, when the drill is in the hole, and the nut F screwed up tight, the sides ofthe chuck are pressed against the drill with corresponding force, and the drill is securelyT held.

What I claim as my invention, and desire to secure by Letters Patent, is- Y l. The chuck-bolt B D, with an oval or elongated hole encircling the -drill-shank, and securing the same with one nut, substantially as set forth and described.

2. The combination of the chuck A and the chuck-bolt B D, substantiallyv as and for the HUGH THOMAS.

Witnesses:

WILLIAM MGFAUL, G. B. LEDDoN. 

